1. Field of the Invention
The present invention relates to a power supply system for a vehicle, and, more particularly, to a power supply system for a vehicle which can be disabled from supplying electric power to at least those control systems dispensable to driving until the ignition key is turned to the ignition position.
2. Description of the Related Art
Typically, a power supply apparatus for a vehicle which includes a single master station and a plurality of remote stations grouped according to functions of electric equipments, which are connected to multiplex communication lines, is provided with a mode control switch for changing the remote stations between a sleep mode and an alive mode. The mode control switch places the remote stations in the sleep mode when all switches including an ignition switch and switches of the electric equipments are off so as to reduce a dark current. Such a power supply apparatus is known from, for instance, Japanese Unexamined Patent Publication No. 4-283140.
The prior art power supply apparatus leaves the remote stations still connected to a power source in the sleep mode, yielding a fall in dark current only to a certain limited extent and providing consumption of electric power even in the sleep mode. If the vehicle is left with the power supply apparatus in the sleep mode for a long time, for instance, before shipping, the battery possibly runs down.